What you find online may be interesting -- that man-in-the- street stuff has its moments -- but by and large it's put together by amateurs. Real journalism comes from professionals.

It's been fascinating watching this idea get turned on its head.

Last week, Time magazine finally flew into the flame that it's been circling for months: It ran a cover story on cyberporn.

It was a bold, sweeping story, an authoritative look at a pressing national issue. The story was dense with facts and figures about how much porn is out there and who's downloading it -- new data from a Carnegie Mellon University study of online pornography that Time had secured an exclusive on.

STUDY KEPT SECRET

Though the article didn't mention it, there was cause for Time to worry about the study's reliability. Unlike most academic studies, whose authors have their peers check their work before they commit it to print, this one was kept secret until it was published, in the student-edited Georgetown Law Journal. Its author, Martin Rimm, is an undergraduate student of electrical and computer engineering with no apparent experience in conducting a study of this kind.

ONLINE

Robert Rossney And some of the study's conclusions are extraordinary -- particularly the finding that 83.5 percent of all images posted to Usenet's .binaries groups are pornographic.

But although experts Time contacted before running the story raised all of these concerns, Time kept to itself any misgivings it had about the study. It wasn't until Time and the Georgetown Law Journal were both on the stands that the study hit the fan.

Overnight, people were discussing the study everywhere online. In the WELL's media conference. On Usenet in the alt.censorship and other newsgroups. In mailing lists. Within a few days, the flaws in Rimm's study were common knowledge online.

Some of the "amateurs" who critiqued the study were pretty formidable. Donna Hoffman and Tom Novak, for example. They're associate professors of management at Vanderbilt University who specialize in "computer-mediated marketing" -- studying how marketing and commerce can take place in the online world. Indeed, Hoffman was one of the experts Time consulted (and disregarded) before running the story.

Hoffman and Novak know a lot about how to study what people online are doing. According to them, Rimm's study gets just about everything wrong. Its methodology is bad, its definitions are bad, it doesn't study what it purports to study, it's not reproducible, it's incoherent and obscure and its author disguised all of these flaws by choosing a publishing venue that would make the study appear credible without subjecting it to prepublication peer review.

Jim Thomas, a professor of sociology and criminal justice at Northern Illinois University, looks at the study from another angle. Thomas says that if the study were conducted the way Rimm says it was, then it "violates fundamental canons against deceptive data gathering, informed consent and revelation of potentially harmful information."

Brian Reid at Digital Equipment Corp., who developed some of the statistical tools that Rimm used to conduct his study, says, "I am so distressed by its lack of scientific credibility that I don't even know where to begin critiquing it. . . . In this study I have trouble finding measurement techniques that are not flawed."

FAULTY CONCLUSIONS

And David Post, a visiting law professor at Georgetown University who has reviewed the study, has this to say about the 83.5 percent figure: "Rimm's conclusion is the precise methodological equivalent to the following: (a) restricting a study of printed pornography to magazines located in the 'adult' area of a bookstore, (b) finding that 83.5 percent of the reader submissions during a one-week period were to magazines that contained 'pornographic' material, and concluding (c) that 83.5 percent of all reader submissions to all magazines are pornographic."

All of the above critiques can be found on Hoffman and Novak's Project 2000 Web site, along with links to Time's article, Rimm's study and more. The URL is www2000.ogsm.vanderbilt.edu.

The long and the short of it is that Time blew it. The hook on which they hung a big, lurid, publicity-getting cover story turns out to have been a stinker. The professionals screwed this up, and it's been the amateurs who have gotten it straight.

Sadly, it's now an unkillable sound bite: Four out of five pictures on the Internet are pornographic.

This is what CNN, the Associated Press and United Press International have reported. It's what Senator Charles Grassley of Iowa said when he read from the issue of Time on the Senate floor. It's found its way onto "Entertainment Tonight." It's hooey, but it will live forever.